Tire inflation system with integrated wheel seal

ABSTRACT

An axle assembly includes a non-rotating component and a wheel hub supported for rotation relative to the non-rotating component about an axis. The wheel hub includes a hub air passage that has a hub inlet and a hub outlet to be fluidly connected to at least one tire. An air chamber is formed at least in part between the non-rotating component and the wheel hub. The air chamber receives air flow from an air source and directs air flow into the hub inlet. A seal assembly engages the wheel hub to seal the air chamber.

TECHNICAL FIELD

The subject invention relates to an axle that includes an air passagethat forms part of a tire inflation system. More specifically, the airpassage is formed at least in part between a rotating wheel hub and anon-rotating component, and is sealed by an integrated seal assembly.

BACKGROUND OF THE INVENTION

Tire inflation systems are used on vehicles, such as tractor-trailervehicles for example, to maintain tire inflation pressures at a desiredtire pressure setting. The tire inflation system draws pressurized airfrom on-board air tanks and supplies this air to an under-inflated tirewhen tire pressure falls below the desired tire pressure setting.

Drive axles present challenges for routing air from the air tanks to thetires. Typically, air hoses must be routed externally of the axlecomponents and around the outside of the tires. Such a routingconfiguration takes up a significant amount of packaging space thatcould otherwise be used for other vehicle components. Further, due tothe external mounting, a significant portion of the air hoses is exposedto potentially damaging contact from rocks, debris, etc.

SUMMARY OF THE INVENTION

An axle assembly includes an air passage for fluid communication with atire inflation system. The axle assembly includes a non-rotatingcomponent and a wheel hub supported for rotation relative to thenon-rotating component about an axis. The air passage is formed at leastin part between the wheel hub and the non-rotating component, and issealed with a seal assembly.

In one example, the wheel hub includes a hub air passage that has a hubinlet and a hub outlet to be fluidly connected to at least one tire. Thenon-rotating component comprises a spindle that rotatably supports thewheel hub. An air chamber is formed at least in part between the spindleand the wheel hub. The air chamber receives air flow from an air sourceand directs air flow into the hub inlet. A seal assembly engages thewheel hub to seal the air chamber.

In one example, the seal assembly includes first and second seals thatare in sealing engagement with the wheel hub and the non-rotatingcomponent.

In another example, the seal assembly comprises a cartridge seal withseal portions that are in contact with the wheel hub and thenon-rotating component. The seal portions engage each other, and the airchamber is formed between the seal portions.

In one example, the non-rotating component comprises a spindle thatrotatably supports the wheel hub and the air chamber is defined in partby a manifold that is fixed to the spindle. The manifold includes afirst passage to direct air from an air source to the air chamber. Theseal assembly seals against an inner surface of the wheel hub and anouter surface of the manifold to form the air chamber. The manifold alsoincludes a second passage to direct lubricating fluid to the seals.

In another example, the non-rotating component comprises an annular ringthat surrounds an inboard end of the wheel hub. The air chamber isdefined within the annular ring at the inboard end of the wheel hub. Theseal assembly includes a first seal that engages the annular ring and anouter peripheral surface of the wheel hub and a second seal that engagesthe annular ring and an inner peripheral surface of the wheel hub todefine the air chamber.

In one example, the axle assembly is a drive axle and includes an axleshaft that is driven by a power source. The axle shaft is coupled todrive the wheel hub about an axis of rotation relative to the spindle.

These and other features of the present invention can be best understoodfrom the following specification and drawings, the following of which isa brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a drive axle assembly in fluidcommunication with a tire inflation system.

FIG. 2 is one example of an air passage formed between a spindle and awheel hub.

FIG. 3 is another example of an air passage formed between a spindle anda wheel hub.

FIG. 4 is another example of an air passage formed between a spindle anda wheel hub.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a drive axle 10 receiving driving input from a power source12, such as an engine or electric motor for example. The driving inputdrives an input gear assembly 14 that includes a differential mechanismas known. The gear assembly 14 drives axle shafts 16 that are coupled todrive wheel end assemblies 18. One example of a wheel end assembly 18 isshown to the left of FIG. 1. It should be understood that the oppositewheel end assembly 18 would be similarly configured.

The wheel end assembly 18 includes a non-rotating spindle 20 that ismounted to an axle housing 22. The axle housing 22 houses the gearassembly 14 and axle shafts 16. A wheel hub 24 is rotatably supported onthe spindle 20 by bearings 26. A tire 28 and associated rim are mountedfor rotation with the wheel hub 24 about an axis A.

A tire inflation system 30 includes an air supply reservoir or tank 32that is used to supply air to the tires 28 when the tires 28 becomeunder-inflated. The tire inflation system 30 includes a control 34 thatdetermines when air is to be supplied and also controls the amount ofair supplied as known. The control 34 can be automatically activated viaan electronic control unit or other similar device to control the amountof air supplied, or the control 34 can be manually actuated by a vehicleoperator. The control 34 can include various valves, sensors, pressureregulators, etc. as known to control distribution of the air from thetank 32. The control 34 is also configured to stop supplying air to atire if pressure falls below a certain level to prevent the tank 32 frombeing depleted of air, such as when a tire has experienced a blow-outfor example.

The control 34 supplies air to the wheel end assembly 18 which includespassages that convey the air to the tire 28. FIG. 2 shows one example ofa wheel end assembly 18 as used with the tire inflation system 30. Thewheel hub 24 includes an outer peripheral surface 40 and an innerperipheral surface 42 that surround the axis of rotation A. The wheelhub 24 also includes an inboard end 44 and an outboard end 46 with amounting flange portion 48 that can be used to mount other brake orwheel structures.

An air chamber 52 is formed at least in part between the wheel hub 24and a non-rotating component, such as the spindle 20 for example. Asshown in FIG. 2, the spindle 20 includes an outer peripheral surface 50that is spaced radially inwardly of the inner peripheral surface 42 ofthe wheel hub 24. The air chamber 52 is defined within a space formedbetween the wheel hub 24 and the spindle 20.

A seal assembly 56 is integrated into the wheel end assembly 18 to sealthe air chamber 52. The seal assembly 56 directly seals against theinner peripheral surface 42 of the wheel hub 24.

In the example in FIG. 2, a manifold 58 is fixed to the outer peripheralsurface 50 of the spindle 20. The manifold 58 includes an innerperipheral surface 60 that is seated against the spindle 20 and an outerperipheral surface 62 that is spaced radially inwardly relative to theinner peripheral surface 42 of the wheel hub 24 to define the airchamber 52. The manifold 58 and seal assembly 56 are positioned at theinboard end 44 of the wheel hub 24 such that the air chamber 52 isinboard of the wheel bearings 26.

The manifold 58 includes an inlet port 64 that is connected to the airtank 32 with a conduit or hose 66. The manifold includes a first passage68 that that directs air from the inlet port 64 to the air chamber 52.

The seal assembly 56 includes at least a first seal 56 a and a secondseal 56 b that is axially spaced from the first seal 56 a along the axisA. The first 56 a and second 56 b seals both directly engage the innerperipheral surface 42 of the wheel hub 24 and the outer peripheralsurface 62 of the manifold 58.

The manifold 58 includes an outlet port 70 that empties into the airchamber 52 at a position between the first 56 a and second 56 b seals.The manifold 58 also includes a second passage 72 that directslubricating fluid to the seal assembly 56. The second passage 72 extendsfrom a lubrication cavity 74 formed between the inboard bearing 26(FIG. 1) and the first seal 56 a to a lubrication cavity 76 that ispositioned inboard of the second seal 56 b. A third seal 56 c sealinglyengages the inner peripheral surface 42 of the wheel hub 24 and theouter peripheral surface 62 of the manifold to seal the lubricationcavity 76. This prevents lubricating fluid from exiting the wheel endassembly 18 at the inboard end 44 of the wheel hub 24.

Air enters the manifold 58 through the inlet port 64 and exits into theair chamber 52. Air then enters a hub passage 78 that is formed withinthe wheel hub 24. The hub passage 78 can be formed through the hub body,hub flange portion 48, through a wheel stud hole, etc. The hub passage78 includes a hub inlet 80 and a hub outlet 82 that is fluidly connectedto at least one of the tires 28.

FIG. 3 shows another example of a wheel end assembly 118 as used withthe tire inflation system 30. A wheel hub 124 includes an outerperipheral surface 140 and an inner peripheral surface 142 that surroundthe axis of rotation A. The wheel hub 124 also includes an inboard end144 and an outboard end 146 with a mounting flange portion 148.

The spindle 120 includes an outer peripheral surface 150 that is spacedradially inwardly of the inner peripheral surface 142 of the wheel hub124. A seal assembly 156 is integrated into the wheel end assembly 118to seal an air chamber 152. The seal assembly 156 directly seals againstthe inner peripheral surface 142 of the wheel hub 124.

In the example of FIG. 3, the non-rotating component comprises anannular ring 158 is positioned to surround the inboard end 144 of thewheel hub 124 at a position where an ABS tone ring would typically bemounted. The annular ring 158 is a stationary, i.e. non-rotatingcomponent, which can be fixed to the spindle 120 or to anothernon-rotating axle or brake component. The annular ring 158 has a C-shapecross-section with a vertical wall portion 158 a and first 158 b andsecond 158 c lateral flange portions that extend axially away fromopposing ends of the vertical wall portion 158 a.

The first 158 b and second 158 c lateral flange portions extend in adirection that is generally parallel to the axis A. The first lateralflange portion 158 b defines an outer peripheral surface 160 of theannular ring 158 and the second lateral flange portion 158 c defines aninner peripheral surface 162 of the annular ring 158. The first 158 band second 158 c flange portions are positioned in an overlappingrelationship with the inboard end 144 of the wheel hub 124. The firstlateral flange portion 158 b is positioned radially outwardly of theouter peripheral surface 140 of the wheel hub 124 and the second lateralflange portion 158 c is positioned radially inwardly of the innerperipheral surface 142 of the wheel hub 124. The air chamber 152 isformed within the annular ring 158 at the inboard end 144 of the wheelhub 124 at a position that is between the first 158 b and second 158 clateral flange portions.

The vertical wall portion 158 a includes an inlet port 164 that isfluidly connected to the air tank 32 with a conduit or hose 166. Theport 164 directs air into the air chamber 152.

The wheel hub 124 includes a hub passage 176 that is formed within abody of the hub between the inner 142 and outer 140 peripheral surfaces.The hub passage 176 includes a hub inlet 178 that is formed in aninboard end face 180 of the wheel hub 124. A portion of the hub passage176 extends in a direction that is generally parallel to the axis A to ahub outlet 182 that is to be fluidly connected to at least one of thetires 28.

The seal assembly 156 includes a first seal 156 a and a second seal 156b that is spaced radially inwardly from the first seal 156 a. The firstseal 156 a is sealingly engaged between an inner surface of the firstlateral flange portion 158 b and the outer peripheral surface 140 of thewheel hub 124. The second seal 156 b is sealingly engaged between aninner surface of the second lateral flange portion 158 c and the innerperipheral surface 142 of the wheel hub 124. The first 156 a and second156 b seals allow the wheel hub 124 to rotate and maintain the airchamber 152. Air is directed through the annular ring 158, into the airchamber 152, into the hub passage 176, and then exits to the tire 28.The hub passage 176 can extend through the hub body, hub flange, wheelmount hole, etc., as described above.

FIG. 4 shows another example of a wheel end assembly 218 as used withthe tire inflation system 30. A wheel hub 224 includes an outerperipheral surface 240 and an inner peripheral surface 242 that surroundthe axis of rotation A. The wheel hub 224 also includes an inboard end244 and an outboard end 246 with a mounting flange portion 248.

The spindle 220 includes an outer peripheral surface 250 that is spacedradially inwardly of the inner peripheral surface 242 of the wheel hub224. An air chamber 252 is defined, at least in part, within a spaceformed between the wheel hub 224 and the spindle 220.

A seal assembly 256 is integrated into the wheel end assembly 218 toseal the air chamber 252. The seal assembly 256 directly seals againstthe inner peripheral surface 142 of the wheel hub 124 and against theouter peripheral surface 250 of the spindle 220.

In the example of FIG. 4, the seal assembly 256 includes a first seal256 a and a second seal 256 b; however, the seal assembly 256 could alsocomprise a cartridge seal formed as a single unit with first and secondseal portions that respectively correspond to the first 256 a and second256 b seals described below. The seal assembly 256 is positioned at theinboard end 244 of the wheel hub 224 at a position that is inboard ofboth wheel bearings 26.

The first seal 256 a is fixed for rotation with the wheel hub 224 andthe second seal 256 b is fixed to the spindle 220. The first seal 256 aincludes a first portion 260 that seats against the inner peripheralsurface 242 of the wheel hub 224. An opening 266 is formed within thefirst portion 260 and is in fluid communication with a hub passage 268formed within the wheel hub 224. The hub passage 268 includes a hubinlet 270 at the air chamber 252 and a hub outlet 272 that is fluidlyconnected to the tire 28.

The first seal 256 a includes a second portion 274 that extendstransversely to the first portion 260 to contact the second seal 256 b.A spring or other resilient retaining mechanism 276 biases the secondportion 274 against the second seal 256 b.

The second seal 256 b includes a first portion 280 that seats againstthe outer peripheral surface 250 of the spindle 220. The second seal 256b includes a second portion 282 that that extends transversely to thefirst portion 280 to contact the first seal 256 a. A spring or otherresilient retaining mechanism 284 biases the second portion 282 againstthe first seal 256 a.

The second portion 282 is seated against a flange 288 of the spindle 220and includes an opening 290 that is in fluid communication with a port292 formed in the flange 288. The port 292 is in fluid communicationwith the air supply via a conduit or hose connection 294.

Each of the wheel end assemblies set forth above provide a simple andeffective fluid connection for directing air from a supply, through adrive axle, and to an associated tire. Further, these configurationsreduce the number and length of hoses that are routed externally of thedrive axle to provide a more robust system.

Although a preferred embodiment of this invention has been disclosed, aworker of ordinary skill in this art would recognize that certainmodifications would come within the scope of this invention. For thatreason, the following claims should be studied to determine the truescope and content of this invention.

1. An axle assembly comprising: a non-rotating component; a wheel hub supported for rotation relative to said non-rotating component about an axis, said wheel hub including a hub air passage having a hub inlet and a hub outlet to be fluidly connected to at least one tire; an air chamber formed at least in part between said non-rotating component and said wheel hub, said air chamber to receive air flow from an air source and directing air flow into said hub inlet of said hub air passage; and a seal assembly engaging said wheel hub to seal said air chamber.
 2. The axle assembly according to claim 1 wherein said non-rotating component comprises a non-rotating spindle, and including at least one wheel bearing that rotatably supports said wheel hub for rotation relative to said non-rotating spindle, and wherein said wheel hub includes an inboard end that extends circumferentially around said non-rotating spindle with said air chamber being formed at said inboard end at a position that is inboard of said at least one wheel bearing.
 3. The axle assembly according to claim 2 wherein said non-rotating spindle includes an outer peripheral surface and said wheel hub includes an inner peripheral surface that is spaced radially outwardly relative to said outer peripheral surface, and wherein at least a portion of said air chamber is formed between said inner and said outer peripheral surfaces.
 4. The axle assembly according to claim 3 wherein said seal assembly includes at least first and second seals with at least one of said first and second seals contacting a rotating surface and the other of said first and second seals contacting a non-rotating surface.
 5. The axle assembly according to claim 3 wherein said seal assembly includes at least separate first and second seals wherein one of said first and said second seals directly engages said inner peripheral surface of said wheel hub.
 6. The axle assembly according to claim 3 including a manifold that is fixed to said outer peripheral surface of said non-rotating spindle, said manifold including a first port to receive air flow from the air source and a first passage that directs air flow through said manifold to said air chamber.
 7. The axle assembly according to claim 6 wherein said air chamber is formed between an outer surface of said manifold and said inner peripheral surface of said wheel hub, and wherein said seal assembly includes at least first and second seals that are mounted between said inner peripheral surface and said outer surface of said manifold, and which are axially spaced apart from each other along said axis to define said air chamber.
 8. The axle assembly according to claim 7 wherein said manifold includes a second passage that directs lubricating fluid adjacent to edges of said first and said second seals that are outward of said air chamber.
 9. The axle assembly according to claim 8 including a third seal positioned inboard of said first and second seals to define a lubrication chamber between said third seal and one of said first and said second seals.
 10. The axle assembly according to claim 7 wherein said hub inlet is positioned axially between said first and said second seals.
 11. The axle assembly according to claim 1 wherein said non-rotating component comprises an annular ring that extends inboard of an inboard end face of said wheel hub, and wherein said seal assembly includes at least first and second seals that are mounted within said annular ring and which are radially spaced apart from each other in a direction extending away from said axis.
 12. The axle assembly according to claim 11 wherein said annular ring comprises a C-shape cross-section with a vertically extending wall portion, a first lateral flange extending from an upper end of said vertically extending wall portion in a direction generally parallel to said axis, and a second lateral flange extending from a lower end of said vertically extending wall portion in a direction generally parallel to said axis, and wherein said annular ring includes an air port formed within said vertically extending wall portion to receive air from the air source, and wherein said first seal engages an outer surface of said wheel hub and an inner surface of said first lateral flange and said second seal engages said inner peripheral surface of said wheel hub and an inner surface of said second lateral flange to define said air chamber.
 13. The axle assembly according to claim 12 wherein said hub inlet is formed in said inboard end face of said wheel hub and initially extends in a direction that is generally parallel to said axis.
 14. The axle assembly according to claim 1 wherein said non-rotating component comprises a non-rotating spindle, and wherein said seal assembly includes at least a first seal portion that is fixed to an inner peripheral surface of said wheel hub and a second seal portion that is fixed to an outer peripheral surface of said non-rotating spindle, and wherein said air chamber is formed between said first and said second seal portions.
 15. The axle assembly according to claim 14 wherein said first seal portion includes a first port that is fluidly connected to said hub inlet and said second seal portion includes a second port that is fluidly connected to receive air from the air source.
 16. The axle assembly according to claim 15 wherein said first seal portion has a first segment that is biased against, and in direct contact with, said second seal portion and wherein said second seal portion has a second segment that is biased against, and in direct contact with, said first seal portion.
 17. The axle assembly according to claim 1 including an axle shaft receiving driving input from a power source, said axle shaft being coupled to drive said wheel hub about said axis of rotation. 